1. Field of the Invention
The present invention relates to a security system for a vehicle and more particularly, to such a vehicle security system, which allows the user to selectively adjust the alert grade.
2. Description of Related Art
Regular vehicles are commonly equipped with a security system for protection against thieves. A vehicle security system is known comprising a security controller mounted in the car, a plurality of sensors installed in the car at different locations and electrically connected to the security controller, and a remote controller carried by the car owner. Immediately after leaving the car, the car owner will press the control button of the remote controller to activate the alert mode of the security system. However, regular vehicle security systems provide only one single alert grade, i.e., the sensitivity of the sensors that are electrically connected to the security controller is fixed. Further, a vehicle may be parked in any climatic environment, for example, fine and cloudless weather, thunderous weather, snowy weather, etc. The sensitivity of the sensors of a vehicle security system that suits fine and cloudless weather may be not suitable for a thunderous or stormy weather. It is frequently seen that the alarm of the security system of a car alarms due to a sharp weather change, especially in abrupt changes of atmospheric pressure.
Further, parking a car in a different place may require a different alert grade. For example, the alert grade may be relatively lowered when parking the car in the house. On the contrary, the alert grade should be relatively higher if the car is parked in the street.
Therefore, it is desirable to provide a vehicle security system that allows the user to adjust the alert grade to suit different conditions.